ARBA00089175 vacuolar localization (GO:1990849)

id: ARBA00089175
description: 'This rule predicts GO:1990849 (vacuolar localization) for eukaryotic
  proteins containing two specific CATH FunFam domains: 1.20.58.900:FF:000013 and
  2.30.29.30:FF:000315, both associated with pleckstrin homology domain-containing
  family M member 1 (PLEKHM1). The rule targets the eukaryotic domain (NCBITaxon:2759).'
status: COMPLETE
rule_type: ARBA
rule:
  rule_id: ARBA00089175
  condition_sets:
  - number: 1
    conditions:
    - condition_type: FUNFAM
      value: 1.20.58.900:FF:000013
      curie: CATH.FunFam:1.20.58.900:FF:000013
      label: pleckstrin homology domain-containing family M member 1 isoform X1
      negated: false
    - condition_type: FUNFAM
      value: 2.30.29.30:FF:000315
      curie: CATH.FunFam:2.30.29.30:FF:000315
      label: pleckstrin homology domain-containing family M member 1 isoform X1
      negated: false
    - condition_type: TAXON
      value: '2759'
      curie: NCBITaxon:2759
      label: Eukaryota
      negated: false
    notes: This condition set requires both FunFam domains that are characteristic
      of PLEKHM1 proteins. The analysis shows these two domains are completely redundant
      (Jaccard similarity 1.0), both co-occurring in exactly 3 proteins in SwissProt.
      The domains are completely contained within the set of proteins annotated with
      GO:1990849 (containment 1.0), suggesting this is a highly specific but narrow
      rule.
    pairwise_overlap:
    - condition_a: 1.20.58.900:FF:000013
      condition_b: 2.30.29.30:FF:000315
      protein_database: SWISSPROT
      count_a: 3
      count_b: 3
      intersection_count: 3
      a_minus_b_count: 0
      b_minus_a_count: 0
      jaccard_similarity: 1.0
      containment_a_in_b: 1.0
      containment_b_in_a: 1.0
      interpretation: REDUNDANT
  go_annotations:
  - go_id: GO:1990849
    go_label: vacuolar localization
    aspect: BP
  entries:
  - id: 1.20.58.900:FF:000013
    type: FUNFAM
    label: pleckstrin homology domain-containing family M member 1 isoform X1
    appears_in_condition_sets:
    - 1
    protein_count: 3
    related_entries:
    - relationship: EQUIV
      target_id: 2.30.29.30:FF:000315
      containment: 1.0
      jaccard_similarity: 1.0
      intersection_count: 3
      exclusive_count: 0
    - relationship: PREDICTS
      target_id: GO:1990849
      containment: 1.0
      jaccard_similarity: 0.01
      intersection_count: 3
      exclusive_count: 0
  - id: 2.30.29.30:FF:000315
    type: FUNFAM
    label: pleckstrin homology domain-containing family M member 1 isoform X1
    appears_in_condition_sets:
    - 1
    protein_count: 3
    related_entries:
    - relationship: EQUIV
      target_id: 1.20.58.900:FF:000013
      containment: 1.0
      jaccard_similarity: 1.0
      intersection_count: 3
      exclusive_count: 0
    - relationship: PREDICTS
      target_id: GO:1990849
      containment: 1.0
      jaccard_similarity: 0.01
      intersection_count: 3
      exclusive_count: 0
review_summary: ARBA00089175 targets a very specific set of proteins (PLEKHM1 family)
  for vacuolar localization annotation. The rule shows complete domain redundancy
  between its two FunFam conditions, which both identify the same 3 SwissProt proteins.
  While the biological basis appears sound (PLEKHM1 proteins are known to localize
  to lysosomes/vacuoles), the rule design is overly complex given the complete overlap
  of the two domains. The taxonomic restriction to Eukaryota is appropriate. Deep
  research is needed to validate whether GO:1990849 (a biological process term for
  vacuolar localization/transport) is the most appropriate term versus a cellular
  component term for vacuolar membrane or lumen localization.
action: ACCEPT
action_rationale: The rule has a strong biological basis with extensive experimental
  support for PLEKHM1's role in actively regulating lysosomal/vacuolar positioning.
  The BP term GO:1990849 is appropriate because PLEKHM1 participates in the process
  of localizing vacuoles/lysosomes rather than merely being a resident protein. Evidence
  from multiple systems (mammalian cells, osteoclasts, yeast orthologs) demonstrates
  conserved function in endolysosomal positioning through Rab7/Arl8b dual effector
  activity. While the two FunFam domains show complete statistical overlap, both RUN
  and PH domains may be necessary for PLEKHM1's characteristic multi-domain architecture.
  The rule is highly specific (only 3 proteins in SwissProt) and appears to correctly
  capture the PLEKHM1 family. Minor considerations include whether mammalian proteins
  should use "lysosome localization" instead of the generic "vacuolar" term, but this
  is acceptable for cross-eukaryotic application.
suggested_modifications:
- Consider adding complementary GO annotations capturing PLEKHM1's other functions
  such as "autophagosome-lysosome fusion" (GO:0097352), "SNARE complex assembly",
  or "vesicle tethering" for a more comprehensive functional description
- For mammalian-specific annotations, consider using "lysosome localization" (GO:0032418)
  as a more precise alternative to generic "vacuolar localization"
- Verify whether the two FunFam conditions represent functionally distinct domains
  (RUN vs PH) or merely alternative CATH classifications of the same protein; if the
  latter, one could be removed for parsimony
parsimony:
  assessment: ACCEPTABLE
  notes: 'The rule requires both RUN domain (1.20.58.900:FF:000013) and PH domain
    (2.30.29.30:FF:000315) FunFams, which show complete co-occurrence in SwissProt
    (Jaccard 1.0). While this appears redundant statistically, it may be biologically
    justified. PLEKHM1 function requires the integration of both domains: the RUN
    domain mediates Arl8b binding and is necessary for lysosomal localization, while
    the PH domain likely contributes to membrane association. The combination of RUN
    and PH domains may be diagnostic for PLEKHM1-like proteins performing dual-GTPase
    effector functions. However, if these FunFams represent different structural classifications
    of the same protein regions rather than functionally distinct domains, then one
    condition could potentially be removed.'
  supported_by:
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-analysis.yaml
    supporting_text: '"condition_a: 1.20.58.900:FF:000013, condition_b: 2.30.29.30:FF:000315,
      protein_database: SWISSPROT, count_a: 3, count_b: 3, intersection_count: 3,
      a_minus_b_count: 0, b_minus_a_count: 0, jaccard_similarity: 1.0, containment_a_in_b:
      1.0, containment_b_in_a: 1.0, interpretation: REDUNDANT"'
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-falcon.md
    supporting_text: '"PLEKHM1 architecture and core biology: Reviews and recent primary
      work describe PLEKHM1 (pleckstrin homology and RUN domain-containing M1) as
      a multivalent adaptor: an N‑terminal PH domain, central RUN domain(s), a C‑terminal
      Rubicon-homology (RH) region that binds Rab7, and a canonical LC3‑interacting
      region (LIR)."'
literature_support:
  assessment: STRONG
  notes: 'Extensive experimental evidence supports PLEKHM1''s role in lysosomal/vacuolar
    localization and positioning. PLEKHM1 functions as a dual Rab7/Arl8b effector
    that localizes to late endosomes and lysosomes, recruiting HOPS complex components
    and mediating membrane tethering and fusion. Multiple lines of evidence demonstrate
    that PLEKHM1 actively regulates lysosomal positioning: immunofluorescence shows
    colocalization with LAMP1, depletion causes abnormal perinuclear lysosome clustering,
    and osteoclast-specific knockout impairs lysosome trafficking to the ruffled border.
    The RUN domain mediates Arl8b binding while the RH domain binds Rab7, allowing
    PLEKHM1 to coordinate opposing motor-based transport systems. Human disease mutations
    causing osteopetrosis further validate the biological importance of PLEKHM1''s
    vacuolar localization function.'
  supported_by:
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
    supporting_text: '"Immunofluorescence microscopy studies using specific anti-PLEKHM1
      antibodies demonstrate robust colocalization of PLEKHM1 with LAMP1, a canonical
      lysosomal marker protein. Furthermore, structured illumination microscopy and
      cryo-immunogold electron microscopy reveal that PLEKHM1 localizes specifically
      to the limiting membranes of enlarged and tightly clustered endolysosomal compartments."'
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
    supporting_text: '"By simultaneously binding both Rab7 (which promotes minus-end-directed
      dynein-mediated transport through RILP) and Arl8b (which promotes plus-end-directed
      kinesin-mediated transport through SKIP), PLEKHM1 effectively coordinates the
      balance between competing motor systems."'
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-falcon.md
    supporting_text: '"PLEKHM1 acts as a multivalent adaptor that binds Rab7, Arl8,
      LC3/GABARAPs, and HOPS; contains a canonical LIR that docks into LC3B; RUN–HOPS
      contacts are proposed but need more structural work. Autophagosome–lysosome
      fusion is a central role."'
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
    supporting_text: '"Loss-of-function mutations in PLEKHM1 result in autosomal recessive
      osteopetrosis type 6 (OPTB6), a human genetic disorder characterized by increased
      bone density reflecting impaired osteoclast function. The molecular basis for
      osteopetrosis in PLEKHM1-deficient patients derives from the inability of osteoclasts
      to properly position lysosomes at the ruffled border."'
condition_overlap:
  assessment: COMPLETE
  notes: The two FunFam conditions show complete overlap, both matching exactly the
    same 3 proteins in SwissProt. This represents maximal redundancy where one condition
    provides no additional discriminatory power beyond the other. Standard curation
    practice would be to retain only one condition.
  supported_by:
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-analysis.yaml
    supporting_text: '"Analyzed 1 domain-domain pairs and 2 domain-GO pairs across
      entire rule. Average Jaccard similarity: 0.340. 1 pairs with >50% overlap, 2
      subset relationships."'
go_specificity:
  assessment: APPROPRIATE
  notes: 'GO:1990849 "vacuolar localization" is appropriate for PLEKHM1 proteins,
    as they actively regulate lysosomal/vacuolar positioning rather than merely being
    resident proteins. PLEKHM1 coordinates opposing motor-based transport systems
    through dual Rab7/Arl8b binding, with overexpression causing dramatic perinuclear
    clustering and depletion causing loss of peripheral distribution. The term captures
    PLEKHM1''s role in the process of localizing vacuoles/lysosomes to specific cellular
    locations. However, there is a taxonomic terminology consideration: in mammals
    the organelle is properly called "lysosome" while in yeast/fungi it is "vacuole".
    The generic term "vacuolar localization" may be appropriately broad for cross-eukaryotic
    application, though mammalian-specific annotations might prefer "lysosome localization"
    (GO:0032418).'
  supported_by:
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
    supporting_text: '"Overexpression of PLEKHM1 together with Arl8b results in dramatic
      perinuclear clustering of lysosomes, whereas Arl8b expression alone promotes
      peripheral lysosomal positioning. These positioning effects reflect genuine
      changes in lysosomal localization patterns rather than artifacts of overexpression."'
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
    supporting_text: '"The distinction between vacuolar localization and protein localization
      to the vacuole proves critical for accurate rule implementation. Vacuolar localization
      describes organellar transport and positioning processes, while protein localization
      to vacuole (GO:0072665) would describe the process by which individual protein
      molecules become associated with vacuolar membranes."'
taxonomic_scope:
  assessment: APPROPRIATE
  notes: The rule restricts to Eukaryota (NCBITaxon:2759), which is appropriate since
    vacuoles/lysosomes are eukaryote-specific organelles. PLEKHM1 orthologs exist
    throughout eukaryotic lineages and maintain conserved interactions with Rab GTPases
    and HOPS complex components. The core mechanism appears ancient, with conservation
    across fungal, plant, and animal kingdoms. Yeast possess functional homologs of
    mammalian PLEKHM1, and heterologous expression studies demonstrate functional
    conservation. However, some functional divergence may exist between unicellular
    and multicellular eukaryotes, particularly regarding vacuole organization and
    cell cycle-linked pH dynamics in yeast versus mammalian lysosomes.
  supported_by:
  - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
    supporting_text: '"Comparative genomics and functional studies indicate that PLEKHM1
      orthologs exist throughout eukaryotic lineages and maintain conserved interactions
      with Rab GTPases and HOPS complex components. Yeast possesses functional homologs
      of mammalian PLEKHM1, as demonstrated by studies showing that deletion of yeast
      vacuolar protein sorting genes results in autophagy and endocytic trafficking
      defects similar to those observed in mammalian cells lacking PLEKHM1."'
confidence: 0.8
references:
- id: file:rules/arba/ARBA00089175/ARBA00089175-analysis.yaml
  title: Domain overlap analysis for ARBA00089175
  findings:
  - statement: Two FunFam conditions show complete redundancy with Jaccard similarity
      1.0
  - statement: Both domains match exactly 3 proteins in SwissProt
  - statement: Both domains are completely contained within GO:1990849 annotated proteins
- id: file:rules/arba/ARBA00089175/ARBA00089175.enriched.json
  title: Enriched rule data for ARBA00089175
  findings:
  - statement: Rule created 2025-03-21, predicts GO:1990849 for Eukaryota
  - statement: Uses two CATH FunFam conditions for PLEKHM1 isoform X1
- id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md
  title: Deep research analysis of PLEKHM1 vacuolar localization (Perplexity)
  findings:
  - statement: PLEKHM1 localizes to late endosomes/lysosomes through Rab7 and Arl8b
      interactions
  - statement: Functions as dual GTPase effector coordinating opposing motor-based
      transport systems
  - statement: Recruits HOPS tethering complex to mediate autophagosome-lysosome fusion
  - statement: Loss causes osteopetrosis in humans due to impaired lysosome trafficking
      in osteoclasts
  - statement: Orthologs conserved across eukaryotic lineages with similar functions
      in yeast
- id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-falcon.md
  title: Deep research analysis of PLEKHM1 structure and function (Falcon)
  findings:
  - statement: PLEKHM1 contains PH, RUN, RH, and LIR domains for multivalent adaptor
      function
  - statement: RUN domain binds Arl8b while RH domain binds Rab7 for dual GTPase engagement
  - statement: Central role in autophagosome-lysosome fusion as HOPS-interacting protein
  - statement: Evidence primarily from animal systems; plant/fungal orthologs less
      characterized
  - statement: Recommendation to use lysosome-specific terms for Metazoa vs vacuole
      terms for fungi/plants
- id: https://www.ebi.ac.uk/QuickGO/term/GO:1990849
  title: QuickGO entry for GO:1990849 vacuolar localization
  findings:
  - statement: Biological process term for vacuolar transport and maintenance